Adrian Wistreich, Director of Research at Opinions.ie told the Irish Mirror: "I don't have a personal opinion on the matter but I think the Templemore investigation and the PAC interviews and the level of media coverage in recent weeks is probably a main cause for drop in support.

"People aren't indifferent. These are very strong results.

"People have very strong views with over nine in ten people having a clear view that damage has been caused to the credibility of An Garda Siochana. Overall, 37% say An Garda Siochana has completely lost its credibility while another 54% say its credibility has suffered but could recover.

"So in total we have nine out of ten people feeling the credibility has suffered, while just 7% don't think it has.

"55% think Noirin O'Sullivan should resign, 33% are undecided and just 12% said no.

"Men are much stronger against Noirin O'Sullivan than women.

"63% of men, almost two in three, said she should go while 48% of women think she should go."

When asked about the money gardai plan to spend on public opinion research, Mr Wistreich added: "We do these surveys all the time and they're not that expensive. To do a survey of 1,000 costs no more than €10,000.

"€255,000 is an enormous amount of money to be spending on public opinion research."

The news comes after it was revealed An Garda Siochana plans to spend €255,000 of the taxpayers' money on surveys to find out what the public thinks of it.

There is currently up to 24 separate inquiries, audits and investigations into allegations of alleged wrongdoing including fraud and money laundering.

The Disclosure Tribunal is probing claims of conspiracy by leading members of the force to damage the reputation of garda whistleblower Maurice McCabe.

And O'Sullivan herself is at the centre of the crisis in relation to what she knew about allegations relating to the alleged misappropriation of public and EU cash at Templemore Garda College.